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<div id="version" align=right><b>petsc-3.14.5 2021-03-03</b></div>
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<A NAME="SNESGetIterationNumber"><H1>SNESGetIterationNumber</H1></A>
Gets the number of nonlinear iterations completed at this time.
<H3><FONT COLOR="#CC3333">Synopsis</FONT></H3>
<PRE>
#include "petscsnes.h"
<A HREF="../Sys/PetscErrorCode.html#PetscErrorCode">PetscErrorCode</A> <A HREF="../SNES/SNESGetIterationNumber.html#SNESGetIterationNumber">SNESGetIterationNumber</A>(<A HREF="../SNES/SNES.html#SNES">SNES</A> snes,<A HREF="../Sys/PetscInt.html#PetscInt">PetscInt</A> *iter)
</PRE>
Not Collective
<P>
<H3><FONT COLOR="#CC3333">Input Parameter</FONT></H3>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>snes </B></TD><TD>- <A HREF="../SNES/SNES.html#SNES">SNES</A> context
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Output Parameter</FONT></H3>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>iter </B></TD><TD>- iteration number
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Notes</FONT></H3>
For example, during the computation of iteration 2 this would return 1.
<P>
This is useful for using lagged Jacobians (where one does not recompute the
Jacobian at each <A HREF="../SNES/SNES.html#SNES">SNES</A> iteration). For example, the code
<PRE>
ierr = <A HREF="../SNES/SNESGetIterationNumber.html#SNESGetIterationNumber">SNESGetIterationNumber</A>(snes,&it);
if (!(it % 2)) {
[compute Jacobian here]
}
</PRE>
can be used in your ComputeJacobian() function to cause the Jacobian to be
recomputed every second <A HREF="../SNES/SNES.html#SNES">SNES</A> iteration.
<P>
After the <A HREF="../SNES/SNES.html#SNES">SNES</A> solve is complete this will return the number of nonlinear iterations used.
<P>
<P>
<H3><FONT COLOR="#CC3333">See Also</FONT></H3>
<A HREF="../SNES/SNESGetLinearSolveIterations.html#SNESGetLinearSolveIterations">SNESGetLinearSolveIterations</A>()
<BR><P><B></B><H3><FONT COLOR="#CC3333">Level</FONT></H3>intermediate<BR>
<H3><FONT COLOR="#CC3333">Location</FONT></H3>
</B><A HREF="../../../src/snes/interface/snes.c.html#SNESGetIterationNumber">src/snes/interface/snes.c</A>
<P><H3><FONT COLOR="#CC3333">Examples</FONT></H3>
<A HREF="../../../src/snes/tutorials/ex2.c.html">src/snes/tutorials/ex2.c.html</A><BR>
<A HREF="../../../src/snes/tutorials/ex3.c.html">src/snes/tutorials/ex3.c.html</A><BR>
<A HREF="../../../src/snes/tutorials/ex5.c.html">src/snes/tutorials/ex5.c.html</A><BR>
<A HREF="../../../src/snes/tutorials/ex14.c.html">src/snes/tutorials/ex14.c.html</A><BR>
<A HREF="../../../src/snes/tutorials/ex15.c.html">src/snes/tutorials/ex15.c.html</A><BR>
<A HREF="../../../src/snes/tutorials/ex18.c.html">src/snes/tutorials/ex18.c.html</A><BR>
<A HREF="../../../src/snes/tutorials/ex19.c.html">src/snes/tutorials/ex19.c.html</A><BR>
<A HREF="../../../src/snes/tutorials/ex21.c.html">src/snes/tutorials/ex21.c.html</A><BR>
<A HREF="../../../src/snes/tutorials/ex25.c.html">src/snes/tutorials/ex25.c.html</A><BR>
<A HREF="../../../src/snes/tutorials/ex30.c.html">src/snes/tutorials/ex30.c.html</A><BR>
<A HREF="../../../src/snes/tutorials/ex35.c.html">src/snes/tutorials/ex35.c.html</A><BR>
<BR><A HREF="./index.html">Index of all SNES routines</A>
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